System for reducing or eliminating reaction



Jan. 27,- 1931. J. M. MILLER 1,790,165

SYSTEM FOR REDUCING OR ELI'MINATING REACTION Filed Nov. 1, 1.926

INVENTOR.

Ma 69% W ATTORNEY.

7 65- 1 Betweenthe'point O anda B1. In the plate or anode circuit of the tube V the plate 40 andthei cathode flisalow re i Lacta'nce or by-path condenser K3, for provid ing a shortcircuit 'for the radio frequency componentofthe plate circuit around-thein- .strument I and source B. i V V 7 Between the inputcirouitrorugridfi of: the tube V and-some remote circuit or path, there may exist a capaci ty such as indicated in dot ted-lines at C6; The remote circuit or path may be immediately or remotely coupled or related to the output circuit of the tube V. In the example illustrated, the remote circuit isthe input circuit oftlieftube V1. e The'remotecircuit'or path is coupled, as re gards fluctuating, alternatingcoroscillatory disturbing electro-motii/fe torces, throughthe capacity GG' with'the input circuitjongrid G ofthe tube V, with consequent Ireaction' thereon tendingto instability ofthersystem or to the production of parasitic or undesired oscillations. f j Y i f I Toreduee'or 'eliminate such reac-tion,'ther e is utilized a condenser C5 connected between" the point "and the remote circuit "or ,pathj where the disturbing electro motive-forces' exist.

The point 0, because of'thereactance o fthe' capacity C4 is at a substantially different alternating, fiuetuating or oscillatory "potential from that oftlie' cathode F, the/magm tude offfthe reactanc'e occasioned'bytlie" Ca. paeity 164 being substantial for this 'pur-p'ose and distinguishable froina large, bypassing" or stopping condenser. I I p Between the grid Gr andtlie cathode Fand' plate P are'intra-tube capacities whichmay be designated, respectively, C1 andGQ: f 7 As indicated in Fig. 2, the 'capacitie's'iclj, C4, C5 and CGffor-m in efiectatrue or"WVhe'at-' 1 stone bridge, a network whichimayfbe sub}; stantially perfectly balanced. "one u gate conductor Of the bridge, 'toswit, thesestween the grid G-andthesp'oint (9,isconnectedi theinput elemenu'asS, and'initheaothen conj ugate conductor, extending betweeirtlie cathode F and the point H, is included any suitable'p'ortion'of the rem9te circuit orfpathwherein the disturbing electro motiye iorces" exist. In the example illustrated, in' the sec ond named conjugate COIlClliCtOI is included the input element, as S1; K1 in'theinp'ut; or grid circuit of the tube V1.5

In thisbridge :h reis accordingly utilized anint'ra-tub'e capacity, for" example, 'that' b'e tween the gridGlrand cathode F,"which'cap'ac ityby itselflor in-assoc'iation Witlr addiitional capacity, ifedesired', constitutes or isincludedl inonearmof the-bridge; j

suitable-point,

as the plate P, in the output circuit of the tube V1,is connected a reactance vC3, which, asjindicated, isa= capacity; utilizediin the re lation described in myprior application SeriaLNo. 653,590, filed July 24, 1 923.

indicated in Fig; 2, theicapacity wc3, with the capacityfifibetween thegrid G plate P, form withi'the aforesaidcapacities C1 and G4: a secondtrue'or:"Wheatstonebridge v hichmay' be substantially perfectly bal-- ancedl Tliecapac'ity G 'inay constitute sole- 1t may comprise that capacity and additional external capacity :1

sly:, theic'apacity;between grid and plate, or

turbing electro motive forces"in-the remote" o circuit-"or pathfrom substantially influenc-- bridge is substantially balanced, thereby'efofoscillations; r V ;'Sin1ilarly, the second bridge including the thejpotential of the: grid G by disturbing electro rnotivefforcesiin-the-output circuit of" the tube again yielding as regards tliese @last?named-disturbances stability and preven- I tion-ofj oscillation production; iVhere the "input elements S, K andSl, K1 are tuned or tunable, the reaction 'jof the remote circuit or path uponthesin'put or g-rid G' of 'thetube 1 ingjthe-potential. of the-grid Gr when thefecti'ngistability andpr'eventing production V willusually afi'e'ct the operation ofthe am p'lifier V and will cause it 'to'be'come unstable and to generate self oscillationsf for certain relative tuning ot these-two .circuits.- The ar l rangemen'tor bridge system-described el1m'-* inates or *r'educes this' reaction, preventing 1 self-oscillation and yielding'stability. For" this-purpose the condenser G5 is connected between the-pfoint- O and a point" as H, at

Whichlatten may beo'r' will be" alternating-f or' fluctuati'ng potential high relative to or f differing substantially from the potential ofj the: circuit adjacent'to'the batteries-A and B.

lf'eachiofithetwo;bridgesindicated is sep j aratelyj balanced, Q there will be no, reaction upon theZi-nput element'iorfgrid ofthe'jtubex V regardlessi'offthe phase of the disturb- 6 ingor'reacting electro-motiveforjces.j Ifthe phase fofthelp'otential ofthe remote circuit orfpaith' or}- offthe point is theisa me as V or degrees fronr'the 'phase'of the pp;

tentialflo"f'tliel late 1 ;:1 balance of the. reac tion on the input element or grid offthe tube" out of balance, the lack of'balance in one bridge counteracting" the lack of balance at the other.

1 Generally, it may bie desirableto balance I the bridges-- separatelyfg witlii-respectf to thediiierentidi sturliingelectrdmotive forces.

'V" can be obtainediwhen bothybri'dges are" er'nn'ient; of the Un'ited States for govern mentalpurposes without the payment to me a of any royaltythereon'or thereforfi What I claim is:

l, The methodof re ducingor eliminating the efi'ect upon the input'element associated with'th'e gridand cathode ofa thermionic device of a disturbing potentialin a remotecin. cuit or pathexterna l tobut' influenced by the anode circuit of said device, whichc'omprises connectmg capacltatlve' reactances between the remote circuit or path and the cathode of said thermionic device'to' define a point between them whose potential varies in phase I with the disturbing electron1otive-force' and differs substantially fromsaid cathode, and

impressing the input energy throughi'said input element betweensaid point and thegrid. v

2; The method of reducing or eliminatingthe effects upon the input element associated with the grid and cathode of a thermionic de-' vice of disturbing potentials in the output circuit of said device andin a remote circuit or path, which comprises connecting capacita tlve reactances between the remote circiutor path and the cathode of said thermionic de-' vice to define appoint betweenithem whose po tential varies in phasewith the disturbing 'electro-motive-force and differs substantially 'pointand the I v .3. The combination with a three electrode" thermionic devicehaving input and output :zfrom said cathode, introducing a capacitative reactance between said point and said output circuit, and impressing the input energy through said input; element between said grld.

circuits, of means for reducing or eliminating the eflect exerted through an inherent capacity upon the grid of saidtherm'ionic device of a disturbing potential in a circuit re- -mote from saidoutput circuit, comprising a I bridge in one arm of which is included said. inherent capacity, in another arm of which is i11cludedthe capacity between grid and oath-1 ode of said thermionic device, and the other two arms of which include capacities, an in put element connected in the conjugate con$ duct-or one of whose terminals is connected to the junction of said twofirs't-named arms,

and the other conjugate-conductor ofsaid bridge having impressed thereon the disturbing potentia 1 4. Thecombination with a three electrode thermionic device having input and output circuits, of means for reducing or eliminating the efiect of a disturbing potential in acircuit remote from said outputcircuit-comprising a reactance connected between a point in said input circuit and the cathode of'said thermionic device,va capacityconnected between said point anda point in said remote H circuit or'path ofpotentialsubstantially diif ferent from cathode potential for alternating currents, and an input element having its terconnected, respectively, to said first point thermionic 'device-,

said remote and input circuits being in .conijugate conductors of abridge in dlfie'rent arms ofwhich'are disposed said reactance and ca-,

pacity," other:arms of saidbridge' comprising respectively, impedance'bet ween said remote circuit'forpath and' said input circuit, and im- 'pedance in said inputcircuit ofsa-idtube 5..-;The combination with a three electrode thermionic {device having i'nput' andoutput circuits,ofmeans for'ire ducing or eliminating the efiect of a disturbing'potentialin a circuit .IQIIlQiQQ from said output circuit comprising a capacitati've 'reactance' connected between a point in said circuit andthe cathode; of jsaid' thermionic device, a capacityfconnected between said point and a pointin said remote'circuit 'orpath of potential substantiallydifierentfrom cathode potential for al- I ternating currents, and an input element have,

ing 'its f terminals 'connected, respectively, to said first pointand the g'ridloif said-thermi onic device, said',remote-andinputcircuits I? being in conjugate conductors Ora bridge'lin ditferent arms of which are disposed J said. capacitative reactance and ,fcapacity, other arms of said bridge comprising respectively,-

. impedancebetweensaid IBIIlQtGClI'CUli) or path a andsaid input circuit,'and-impe'dance'between l 1 input elect ro'des of said tube; V 6. The combination with' a three electrode thermionicdevice having input and-output circuits, o;ffmeanjs f r reduci g or eliminating E the efl ect 'ofid sturb ng potentlals n said out,- put c rcu t 7 and in a c rcuit remote ir-omgsa d output circuit comprising i areactance con-1 iotnected between a point in said inputTcir'cuit I: i

and the cathodeofsaid thermionic device, a reactance connected between said pointiaud' said output circuitfacapacity conneicfted betweenasaid point and: acpoint "in said remote circuit of j potential. substantially different fro f athodepotential for alternating' curf rents,ji and an input element having its ter mines. c nn e d', e pec ely; a first? ,juga'te; conductors? offa bridge in difierentf armsfof which aredisposed-said firstamed reactance and'said, capacity, otheriarms of said bridge-comprising respectively, capacity between said. remote" circuit and? said input 1. cir'cu1t,""and impedance between E lnput elecg I trodes -ofsaidtube v r i p 5 7 The combination witha: three electrode and egca heae of s id thermio ic device, capac tat ve; reacta nce j connected between said point and said qutput circuit,acapacityfl connected between'saidfpoint' ma int'iins f point and the gIld of sa d:therm10n1c dev cej, 1 I said'i emotean'd input circuits being incjon- P said remote circuit of potentialsubstantially different from'cathode .potentiali for alternating currents and'an input element having its terminals, H connected,. respectively, to said point andlthe .g ridoi said .thei mionic'device, c

thermionic device, having input :and output circuits and a remote .circuitiassociated with v said /output circuit,,of a bridge having ahca-i pacity in each arm ithereofda capacity inyone ofsaid arms including the capacity between i the grid. and cathode of said thermionic .de-

vice, an inpntreleinent.connectedintone con: jugate. conductor of sald bri-dge anda portion m'ionic device, an input element connected in V oneconjugate. conductor-0f said bridge; second thermionic device, and and-11pm 'cin cuit therefor comprised'in the second conju teconductor of said'bridgeff i 12. The combinationvvithathree electrgxla thermionic device having input and output 'circuit's,.and a ren'iotef circuitTassociated vvith said output circuit of capacities connected in series 'vvith eac hiotheribtween the anode and cathode of said thermionic device and forming a bridge with 'capaciti'esincluding the. grid-anode and grid-cathode capacities of i said thermionic device, an input element 'co'nnected in a conjugate conductor ofsaid bridge, and a. capacityfin a' connection from a pointihtween said jfirst named capacities and a point in saidremotecircuitfofpotential i substantially difi'erent from cathode potential for alternatinggurrents'. j 1

J 1 MILLER ofasaid ri'emotecircuiti'in'cluded in the other.

conjugate conductonofi saidbridge,

9. The combinati ni-xvith aithree'e thermionicgdevice rhaving input and. output t muit's, I and a remote circuitgas'sociated with j said outputcircuim of abridge havinga ca-.

pacity inyachlar'rrithereOf,.a capacity in one the grid andicathodezof said thermionic deof said arms includingrthe capacity! between vice, a second bridge having two arms in com- 7 111011 with said first. named br dge, a third arm: of said second bridge ncludlng capaclty com-- prising the capacityg'between'. plate and grid i of said thermionicdevice said bridges having. 7.

ch1ctorof=saidfirstnamed bridge. v

eeelectrode:

a common conjugate conductonanvinput ele n1ent. connected in said ,icommonrconjugate conductor, and a-portion' of said remote cir- 7 cuit' included Lin the other conjugate. i cone '10 .The 'combinatio ivvitha thr 7 thermionic device having input and output circuits, andflaremote. circuit influenced by said{ output circuit, :o.a bridge having a 'caf pacity in each anti-thereof, a capacityin one; Q

of said farms. including the, capacity between 7 thegrid'andfcathodeof saidthermionic de- I vice, ani lnputuelementconnectedunone cona V -ugate conductor offsaid bridge, a portion;

oi -said remote circuit includedin the other 1 conj ugate conductor of said-bridge, a second 9 bridge including, two of the-capacities ofsaid; first namedbridge, said first-.namedconju; 1

--gate conductor of said first named bridge 'con- I stituting a conjugate conductor of's'aid sec 7 ond'br1dge, a .W1nd1n g1nthe other 0011 ugate conductor of said second. bridge,:and a wind '1ng.,1n.sa1d remote clrcult coupled to said? Winding. i.

' 11 .The combination with athree' electrode 1 thermionicidvice. having inputv and output circuits,of abridgehavinga cap'acityin each arm itheifeo f, ioneof said capacities including 7 ,7 he-en b t ee e etmi i ft dthee- .i. T

lectmd; 

